muscle and motor units

Question 1

what is the first part of 4 of muscle contractions

Answer 1

ap stimulates release of NT across NM junction

Question 2

what is the 3rd part of 4 for muscle contraction

Answer 2

causes release of calcium from sarcoplasmic reticulum

Question 3

whats the 2nd part of muscle contraction

Answer 3

ap spreads across the sarcolemma/ muscle membrane and into fiber along T tubules

Question 4

what is the final step in muscle contraction

Answer 4

calcium binds to the muscle and causes the cross-bridge cycling

Question 5

what are the 3 things shows -

Answer 5

muscle force, temperature and length

Question 6

what is a motor unit

Answer 6

a single neuron and muscle fibres that it innervates

Question 7

where is the motor unit

Answer 7

ventral horn of spinal cord

Question 8

what does a muscle unit do

Answer 8

innervates muscles

Question 9

what is twitch fusion

Answer 9

when twitch fuse due to multiple stimulation of the muscle

Question 10

one ap is what

Answer 10

one muscle twitch

Question 11

what type of electrode is used for artificial stimulation

Answer 11

black anode

Question 12

what is thr frequency variation in hetz

Answer 12

3-30

Question 13

more muslce stimualtion causes what

Answer 13

smoother and a longer muscle twitch

Question 14

twitch properties depend on what

Answer 14

fibre type

Question 15

why does fiber type vary for muscle twitch properties

Answer 15

due to how fast or slow twitch, temperature and fatigue as well as firing rates of different muscles like the glutes vs. eyes

Question 16

what does movement precision depend on

Answer 16

number of motor units

Question 17

the more motor units in a muscle means

Answer 17

finer control and finer force modulation

Question 18

lower innervation number in muscles means

Answer 18

more control

Question 19

calf muscles have less control comapred to the

Answer 19

eye

Question 20

lowest innovation number means

Answer 20

highest amount of control of the muscle

Question 21

you can lose motor neurons from what

Answer 21

motor neuron disease slowly over time

Question 22

action potentials propagate along the ..

Answer 22

sarcolemma

Question 23

AP runs along the sarcolemma to do what

Answer 23

release calcium from sarcoplasmic recticulum

Question 24

what will emg show

Answer 24

the force / activity of motor units acting together

Question 25

does fast twitch has a higher or lower resting membrane potential

Answer 25

higher

Question 26

eccentric contraction is

Answer 26

lengthening

Question 27

concentric contraction is

Answer 27

shortening

Question 28

which is usually has more force con or eccentric

Answer 28

eccentric

Question 29

is torque effected by angle of muscles

Answer 29

yes

Question 30

why is torque effected by angle of msucle

Answer 30

due to more or less distance to travel, bigger angles require more force

Question 31

will overlapped fibres impact muscle fibres

Answer 31

yes - less force

Question 32

why do overlapped muscles not produce as much force

Answer 32

due to actin an myosin overlapping ,

Question 33

fibres are compensated for failing contraction in other

Answer 33

fibres and the force is maintained

Question 34

Muscle fatigue hypothesis is ..

Answer 34

muscle force is reduced when stimulation was maintained at a high rate over time

Question 35

fatigue is

Answer 35

slowing the muscle and slows the force and reduces force

Question 36

what is muscle wisdom

Answer 36

a mechanism that will sense a fatiguing muscle and will reduce the force and fire less through the CNS

Question 37

how does the nervous system know when to reduce motor neuron firing rate (3)

Answer 37

peripheral detection of metabolites like lactate spinal suppression of motor neurons firing and changing in voluntary activation

Question 38

why does the NS reduce the firing of neurons

Answer 38

reduce neuronal fatigue and help maintain fine motor control

Question 39

what could happen when there is a lot of firing of the muscle

Answer 39

loss of control

Question 40

what are the 2 types of fatigue

Answer 40

frequency or force

Question 41

what is low frequency fatigue

Answer 41

caused by intense exercise, takes days to recover and caused by reduced calcium release due to mechanicals damage.

Question 42

what is high frequency fatigue

Answer 42

caused by continuous high-frequency stimulation, recovers quickly after, caused by failure of transmission along muscle membrane

Question 43

can electrical stimulation increase force

Answer 43

yes but not as effective as normal training by 2/3

Question 44

force is modulated by

Answer 44

changing firing rate and or recruiting more units

Question 45

muscle fatigue reduces contraction speed due to what

Answer 45

muscle wisdom

Question 46

muscle fatigue can be partly due to

Answer 46

loss of neural drive - central fatigue

Question 47

what is another way of measuring muscle activity

Answer 47

Acoustomyography or ultra sound

Question 48

what is Acoustomyography (amg)

Answer 48

A method of measuring muscle activity which is intrinsically toed to contraction and the amplitude declines during muscle fatigue